Chausath Khambha is the tomb of Mirza Aziz Kokaltash, Mughal emperor Akbar’s foster brother. It was built in 1623-24 AD. This is the largest open space in Nizamuddin Basti. There are three parts of the complex:

Chaunsath Khamba (tomb of Mirza Aziz Koka)

Urs Mahal (hall, gathering area, courtyard)

Ghalib’s tomb (famous Urdu poet Ghalib)

The restoration of Chaunsath Khamba was done by the Aga Khan Trust, with funding from the German government. If you go there, you'll see the posters showing "before and after" comparisons.